Gold particles are one of the most widely used classes of nanomaterials for chemical, bioanalytical, biomedical, optical and nano-technological applications. Gold nanoparticles can be manufactured in a variety of methods. As a non-limiting example, synthesis of substantially spherical gold nanoparticles that are covered with negatively charged citrate ions can be prepared by using sodium citrate to reduce tetrachloroaurate (HAuCl4 has previously described by Enustun & Turkevich (Enustun, & Turkevich, Journal of the American Chemical Society 1963: 85, 3317-3328).
Cancer detection is based on both structural and functional imaging techniques. Structural techniques (e.g., US, MM and CT) identify anatomic details and provide information on tumor location, size and spread, based on endogenous tissue contrast. However, they are not sufficiently sensitive for detecting critically small tumors or metastases since they lack structural manifestation. The development of the main clinically applicable functional imaging technique, positron emission tomography (PET) using the glucose analog 18F-2-fluoro-2-deoxy-d-glucose ([18F]FDG) has eventually revolutionized the field of medical oncology. [18F]FDG-PET is based on the increased metabolic profile of malignant cells and provides the ability to discern molecular and cellular alterations associated with pathological conditions, even before structural modifications occur. However, [18F]FDG-PET lacks anatomical information, and thus necessitates the incorporation of an additional structural imaging modality such as CT or MM in order to obtain an accurate anatomic localization of the foci of increased metabolic activity. The combination of PET with CT (PET-CT) enables both functional and anatomical information in a single setting. However, in view of the relatively high cost of PET scans, the dependence on the short-lived [18F]FDG (T1/2<2 h) and its non-specificity for cancer which leads to high rate of false positives (glucose uptake is not cancer-specific), the development of a single modality which will overcome these drawbacks is highly desirable.
Although glucose-conjugated gold nanoparticles have been previously reported as contrast agents to image tumors using techniques such as CT or X-ray imaging (US. Pub. No. 9107895), the efficiency of such conjugates remained inadequate. Therefore, the need for an efficient glucose-conjugated gold nanoparticle for CT or X-ray imaging remained.